Seed2Cor

Parallel single component ambient noise correlation from SEED

• Extract SAC & response from SEED
• Remove instrument response
• Temporal (1-bit, run-absolute-mean, cut events) & spectral (whiten) normalization
• Cross/Auto-correlate & stack

Directory structures

• input/: template files for input
• src/: source code
• tools/: auxiliary scripts

Usage

Dependencies

Currently tested on

• RHEL (Red Hat Enterprise Linux): 6.9, 7.3
• gcc: 6.1.0, 4.4.7 20120313 (Red Hat 4.4.7-18)
• FFTW: 3.3.7, 3.3.4 (failed!), 3.2.3
• rdseed 5.3.1
• evalresp 3.3.3

Compile

$ cd src/
$ make

The output could be compared with src/make.log.

Input

• parameters: processing parameters
  • see input/parameters.lst for template
• seed.lst: list of SEED files
  • see input/seed.lst for template
  • use tools/generate_seedlst.sh to generate
• station.lst: list of stations
  • see input/station.lst for template
  • use tools/generate_stationlst.sh to generate
  • optional flag

    0-N
    For stations with same number n (except 0), do cc,
    also do cc with group 0,
    but do not do cc with other numbers.
    For number 0, do cc with all other group,
    but do not do cc with all other group 0 members.
    

Run

$ Seed2Cor parameter_file [nthreads]

A Python wrapper tools/s2c_wrapper.py with a YAML parameter file input/param.yml might be helpful.

Output

File Structure

• yyyy.MMM/
  • yyyy.MMM.dd/
  • COR/: monthly correlations
    • STA/
      • COR_MASTER_SLAVE.SAC
  • COR_D/: daily correlations
    • STA/
      • COR_MASTER_SLAVE_dd.SAC
  • Cor_dayflag.lst: days if data available

SAC Header

• KEVNM: source station
• KSTNM: receiver station
• USER0: # of days stacked

Attention

• The temperal normalization method of 'earthquake cutting' has NOT been well tested. Use with caution!
• The spectrum reshape function is currently removed from the code. (Smooth2() in Whiten.c does nothing)

Reference

Bensen, G. D., Ritzwoller, M. H., Barmin, M. P., Levshin, A. L., Lin, F., Moschetti, M. P., et al. (2007). Processing seismic ambient noise data to obtain reliable broad-band surface wave dispersion measurements. Geophysical Journal International, 169(3), 1239–1260.

Lin, F.-C., Ritzwoller, M. H., & Shen, W. (2011). On the reliability of attenuation measurements from ambient noise cross-correlations. Geophysical Research Letters, 38(11).